Implement proper storage metrics (P0-009)\n\n- Add dedicated storage_metrics table\n- Create StorageMetricReport models with proper field names\n- Add ReportStorageMetrics to agent client\n- Update storage scanner to use new method\n- Implement server-side handlers and queries\n- Register new routes and update UI\n- Remove legacy Scan() method\n- Follow ETHOS principles: honest naming, clean architecture

aggregator-agent/internal/models/storage_metrics.go

@@ -0,0 +1,31 @@
+package models
+
+import (
+	"time"
+
+	"github.com/google/uuid"
+)
+
+// StorageMetricReport represents storage metrics from an agent
+type StorageMetricReport struct {
+	AgentID   uuid.UUID          `json:"agent_id"`
+	CommandID string             `json:"command_id"`
+	Timestamp time.Time          `json:"timestamp"`
+	Metrics   []StorageMetric    `json:"metrics"`
+}
+
+// StorageMetric represents a single disk/storage metric
+type StorageMetric struct {
+	Mountpoint     string                 `json:"mountpoint"`
+	Device         string                 `json:"device"`
+	DiskType       string                 `json:"disk_type"`
+	Filesystem     string                 `json:"filesystem"`
+	TotalBytes     int64                  `json:"total_bytes"`
+	UsedBytes      int64                  `json:"used_bytes"`
+	AvailableBytes int64                  `json:"available_bytes"`
+	UsedPercent    float64                `json:"used_percent"`
+	IsRoot         bool                   `json:"is_root"`
+	IsLargest      bool                   `json:"is_largest"`
+	Severity       string                 `json:"severity"`
+	Metadata       map[string]interface{} `json:"metadata,omitempty"`
+}